1. Field of the Invention
This invention relates to a method of forming a self-aligned contact utilizing a polysilicon etch protectant layer in manufacturing a semiconductor device, and more particularly, to a method of forming a self-aligned contact by providing an etch protectant polysilicon layer as a protective layer to prevent an insulating layer formed on gate electrode from being undesirably etched during the self-aligned contact process.
2. Information Disclosure Statement
Generally, as the integrity of the semiconductor device increases, the area of the unit cell of the semiconductor device decreases which results in a decrease in the processing area available for manufacturing the device. To overcome this problem, during the bit line contact process of the semiconductor device, a self-aligned contact process is used in forming a contact region in the space between word lines, that is, between the gate electrodes in order to make the most of the available space.
However, in the self-aligned contact process as mentioned above, an insulating layer formed on the gate electrode deteriorates during the bit line contact process, which undesirably results in current leakage between the bit line and the word line. In order to prevent this problem, either a polysilicon oxide layer or a nitride layer is utilized as an etch barrier layer for the insulating layer formed on the gate electrode.
Nevertheless, even though a nitride layer or a polysilicon oxide layer is applied as an etch barrier layer according to the prior art, since the etching selectivity of the insulating layer, which has been deposited on the etch barrier layer and is to be removed during the bit line contact process, is the same as that of the etch barrier layer, it cannot properly function during the over etching process of the resulting structure after the main etching process of the insulating layer deposited on the entire surface of the resulting structure is performed.
Therefore, it is an object of the present invention to solve the problem set forth above and to provide a method of forming a self-aligned contact utilizing a polysilicon layer as a protective layer for preventing undesirable etching of the insulating layer formed on the gate electrode, during the self-aligned contact etching process.
The preceding object should be construed as merely presenting a few of the more pertinent features and applications of the invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to both the summary of the invention and the detailed description, below, which describe the preferred embodiment in addition to the scope of the invention defined by the claims considered in conjunction with the accompanying drawings.